The invention is related to transducer carriage drive mechanisms for magnetic diskette systems. Particularly, this invention is concerned with a means for damping the vibrations of the transducer carriage while the latter is being driven by stepping motor operating at a particular frequency during positioning of the read/write heads over the disk surface.
The particular transducer drive system to which the preferred embodiment of this invention is applied is the mechanical system disclosed in U.S. Pat. No. 4,198,871 owned by the assignee of the present application. A transducer positioning system as disclosed therein typically includes a stepping motor which rotates its shaft a predetermined angle for each electrical pulse received by the motor. The shaft of the stepping motor is mechanically linked to a movable transducer carriage through a drive band which converts rotational torque of the stepping motor to a translational force. The translational forces act upon the carriage so that the read/write heads may be positioned over selected tracks on a rotating data storage disk.
A typical positioning controller for a stepping motor will transmit a number of pulses to the stepping motor according to the number of tracks across which the transducer is to be moved. For example, with a one-to-one correspondence between the number of steps and the number of tracks traveled, 50 pulses, or a multiple thereof, will be transmitted by the controller to make the stepping motor advance that carriage, intermittently, 50 tracks across the disk surface. Thus, if each rotational step of the motor shaft is, say 1.8 degrees, rotation of the stepping motor shaft through a total angle of 90 degrees is mechanically translated to the 50-track move, or one inch with a typical track pitch of 0.020 inch. In the motor and mechanical structure employed in the aforementioned patent application, two 1.8 degree rotational steps translate into a one track move. A flexible metal drive band couples the motor shaft to the movable carriage. This link, though flexible, is rigid in the direction of the carriage movement and is generally coupled directly to the carriage.
Undesirable consequences result, however, from the rapid acceleration and deceleration of the carriage mass during pulsing of the stepping motor. Specifically, the rapid start-stop motion of the carriage mass, in reaction with its mechanical environment, generates a substantial amount of audible noise and causes other deleterious inertial effects on the diskette system.
Accordingly, an objective here is to eliminate or substantially reduce the noise so generated, and to reduce harmful effects on the diskette system caused by the associated intermittent force impulses.
It is another object of this invention to dampen the mechanical forces acting upon a movable transducer carriage in a magnetic diskette system.
It is a further object of the invention to reduce the level of noise generally associated with the movement of a transducer carriage by a stepping motor.
It is yet another object of the invention to reduce or eliminate harmful or deleterious effects on a magnetic recording diskette system caused by intermittent acceleration and deceleration forces acting upon the rigid mechanical linkages of the transducer positioning mechanism.
Other objects of the invention will become more readily apparent upon review of the succeeding disclosure taken in connection with the appended drawings.